Golf ball and method of making the same



Sept. 5, 1961 R. P. MoLlToR 2,998,977

GOLF BALL AND METHOD 0F MAKING THE SAME Filed Jan. 16, 1959 Illmnlulmln" INVENTOR. Foe/" j? MaZa'zoP ATTORNEYS United tes Patent O 2,998,977 GOLF BALL AND METHOD OF MAKING THE SAME Robert P. Molitor, South Hadley, Mass., assigner to A. G.

Spalding & Bros., Inc., Chicopee, AMass., a corporation of Delaware Filed Jan. '16, 1959, Ser. No. 787,205 Claims. (Cl. 273-225) This invention relates to game balls and to methods of making the same. More specifically, it pertains to the formation of the centers or cores for such balls as are used in the games of golf, baseball and the like.

Prior to the instant invention, iiuid type cores or centers have successfully been used in golf balls and the like. In manufacturing these cores, it is necessary that a perfect sphere be formed to maintain the balance of the ball after the tensioned winding has been formed around the core and a cover disposed over the winding. Further, it is necessary that the core be formed in such a manner that leakage of the fluid contained therein is prevented.

The present invention eliminates the problems which may be encountered in the manufacture and use of balls having fluid cores by providing a method for making hollow center cores wherein perfect registration of the `core sections is achieved, to the end that a balanced sphere is formed having leakproof joints, and provides an improved core structure which may be readily manu,- factured and assembled by modern production methods.

According to the invention, a pair of complementary resilient core sections, having opposed mating surfaces, are provided with interlockingimeans on the mating surfaces for registering the sections as they are assembled and for forming a leakproof seal under the pressure of the tensioned winding.

It is, therefore, an object of the invention to provide a hollow core, adapted to hold a fluid, for use in golf balls which is self-aligning in assembly to form a perfect sphere and is sealed against leakage of fluid therefrom.

It is also an object of the invention to provide a golf ball having a hollow core, adapted to hold a fluid, which includes a pair of complementary core sections joined in tongue and groove relationship so that a spherical core is maintained under tension and provides a base for winding the strand thereon so as to form a spherical wound ball.

Another object of the invention is to provide a hollow spherical center or core for golf balls and the like which includes a pair of resilient complementary hemispheres, having opposed mating surfaces, one of which is provided with an integral annular ridge on its mating surface and the other with an annular groove in its mating surface adapted to receive the ridge, whereby registration of the hemispheres in assembly is obtained and a leakproof seal is formed when the core is wound under tension.

It is a further objectV of the invention to provide a hollow spherical fluid holding core for golf balls which includes a pair of resilient complementary hemispheres, having opposed mating surfaces, one of which is provided with an annular ridge or tongue on its mating surface and the other with an annular groovein its mating surface adapted to receive the ridge in locked engagement, whereby registration o-f the hemispheres in assembly is obtained and retained and a leakproof seal is formed when the core is wound under tension.

A still further object of the invention is to provide a hollow fluid holding core for golf balls or the like which is readily manufactured and assembled by modern production methods, is preferably balanced to provide the desired flight when embodied in a finished ball and is r4ice sealed against leakage caused by shock from impact and the like.

Other objects and advantages of the invention will be apparent from the specification and claims when considered in connection with the attached sheet of drawings, illustrating one form of the invention, wherein like characters represent like parts and in which:

FIGURE l is a cross-sectional view of a golf ball embodying the invention;

FIG. 2 is an exploded cross-sectional view of a hollow core embodying the invention With a fluid forming pellet;

FIG. 3 is a view taken in the direction of the arrows 3 3 in FIG. 2;

FIG. 4 is a view taken in the direction of the arrows 4-4 in FIG. 2;

FIG. 5 is a cross-sectional view of a core embodying an alternative form of the invention;

FIG. 6 is an exploded cross-sectional view of the core of FIG. 5;

FIG. 7 is a cross-sectional |view embodying another alternative form of the invention; and

FIG. 8 is an exploded cross-sectional view of the core of FIG. 7.

Referring now to the drawings for a more detailed description of the invention, in FIG. l a golf ball generally indicated by the numeral 10 is shown. The golf ball, in accordance with conventional practice, includes a hollow center or core 11 of resilient material having a cavity 12 therein adapted to hold a fluid 13. Outwardly of the core, is formed a tensioned Winding 14 of rubber thread or the like over which is disposed a cover 15 formed ofv cover stock, as is conventional practice.

Prior to the instant invention, lthe cores of golf balls were either molded in one piece and lled with a fluid by a hypodermic needle or the like or were formed in sections, such as complementary hemispheres, which had their mating surfaces bonded together by a cement. When golf balls were formed in the latter manner, the fluid was inserted in the cavity by means of a hypodermic needle after the core sections were assembled or was inserted in one of the core sections in the form of a frozen fluid or as a pellet before the sections were bonded together.

A number of problems are presented when the center or core of the golf ball is formed in sections which are later to be bonded together. First, it is difficult to properly align the sections during the bonding operation so that a perfect sphere is formed with the result that the ball is unbalanced. It will, of course, be understood that any misalignment of the sections Iforming the core will be emphasized in the finished product `as the tensioned Winding is formed around the core. Second, leakage of the fluid from within the core `occurs fbetween the mating surfaces of the core sections, where the bond is formed, this leakage resulting in an increased number of rejections of balls during manufacture and of shortened ilife of the balls when they are placed in use.

The present invention overcomes the problem of misalignment of core sections `during I.assembly and of leakage of fluid from between the sections by providing an improved core structure having means formed integral with the core sections for bringing the same into registration during assembly, whereby perfect balance is achieved, and for sealing the lbonded joint against leakage of fluid from the cavity.

In FIGS. 2 through 4 one form of the improved core or center 11 is shown in detail. A pair of complementary hemispheres 16 and 17, which are preferably formed of elastomeric material such as natural or synthetic rubber or rubberdikematerial, having opposed mating surfaces 18 and 19 are provided with integral interlocking means on the mating surfaces. In the form of the core shown in FIGS. 2 through 4' the hemisphere 16 is provided with an integral annular tapered ridge 20 on its mating surface and the hemisphere 1'7 is formed with a tapered annular groove 2l in its mating surface. According to the invention the groove 2l is of a size and configuration adapted to readily receive the ridge while rictionally retaining it therein. The tapered walls of the ridge or tongue 20 act to facilitate the tongue in groove mating of the parts. It will be readily understood that when the complementary hemispheres 16 and 17 are fitted together ywith the mating surfaces 18 and 19 `complementing one another, that the ridge Z will be snugly received within the groove 2i to register the hemispheres in perfect alignment. In this manner a balanced spherical core is formed when the hemispheres are bonded together. A feature kof the tapered ridge construction is its ability to `dispel air from the groove as the sections are lbeing brought together, thereby enabling la core to be formed having no pockets of trapped air.

It is contemplated, in accordance with the invention, that the uid 13 will be positioned between the hemispheres before they are fitted together, this being accomplished by positioning a capsule or pellet 22 of gelatin iilled with the fluid in the cavity of one of the hemispheres before the sections are assembled. When the core sections are thereafter brought together and bonded in assembled position the curing operation dissolves the gelatin and frees the fluid in the cavity 12.

After the hemispherical core sect-ions I6 and I7 have been assembled as above described, the tensioned winding 14 of rubber thread, or the like, is formed over the core in the conventional manner. The winding, due to the pressure it exerts on the core, acts to compress the walls of groove 21 into locking engagement ywith ridge 20 and in this manner forms a strong fluid tight seal.

`In FIGS. and 6 an alternative form of the invention is shown wherein the hemispherical core section 16 is provided with an integral annular ridge 23 of rectangular cross section which is adapted to be received in a correspondingly formed groove 24 formed in the hemisphere 17. While the tapered walls, of the ridge Ztl, of the embodiment of the invention shown in FIGS. 1 through 4, were designed to facilitate the mating of the ridge with its related groove and to dispel air from the groove, the rectangular construction of the ridge 23 Iand its related groove, is designed to provide closer registration of the core sections, when required, and strengthen the irictional engagement therebetween so that the hemispheres are maintained in assembled position during the initial part of the bonding operation.

Another form of the invention, as shown in FIGS. 7 and 8 provides a structure wherein the engagement of the ridge within the groove locks the hemispheres together against accidental displacement. According to this form of the invention, an undercut annular ridge 25 is formed on the hemisphere 16 and is adapted to be snapped into engagement with a correspondingly undercut groove 26 formed in the mating surface of the other hemisphere 17. It will be seen that, with this form of the invention, when the hemispheres are fitted together, the ridge 25 is snapped past the small mouth of the groove 26 and into locked engagement therein so that the hemispheres are not readily separated.

While other forms of tongue in groove structure may be resorted to, in addition to the embodiments of the invention above described, the basic concepts, of registered alignment of the core sections to obtain a balanced core and compression of the groove against the ridge by the tensioned winding to form a uid tight seal, will maintain.

Thus, among others, the several objects of the invention as `aforenoted are achieved. Obviously, numerous changes in the structure may be resorted to Without departing from the spirit of the invention as defined by the claims.

I claim:

l. In a golf `ball having a hollow, resilient, impervious spherical core member, a fluid under pressure therein, a tensioned winding on said core member and a cover disposed -around the winding; the improvement wherein said core member comprises a pair of complementary hemispherical sections having opposed mating surfaces adapted to be bonded together, one of said sections having an integral annular `ridge formed intermediate the mating surface thereof and said other section having an annular groove formed intermediate its mating surface in which said ridge is disposed and wherein the internal uid pressure and the tensioned winding presses the walls of the groove into sealing relation -with the ridge to seal said core and prevent leakage of fluid from the core to the windings.

2. The invention as in claim 1, wherein said annular ridge is tapered and said annular groove is correspondingly tapered to receive the same.

3. The invention as in claim l, wherein said annular ridge is undercut and said annular groove is correspondingly undercut so that said ridge is snapped into said groove to be retained therein.

4. In a golf ball having a hollow, resilient, impervious spherical core member having therein a fluid under pressure, a tensioned winding on said core member and a cover disposed around a winding; the improvement wherein said core member comprises a pair of hollow complementary hemispherical sections having opposed coplanar mating surfaces adapted to be bonded together, one of said sections having an integral annular ridge formed intermediate the mating surface thereof and said other section having an annular groove formed intermediate its mating surface adapted to receive said ridge whereby said core is sealed and said sections are aligned, and in which said tensioned winding and internal pressure compresses said groove against said ridge to retain the ridge in the groove and reinforce the sealing of said core.

5. The method of making a golf ball comprising the steps of forming a pair of hollow complementary resilient core sections with opposed coplanar surfaces provided with a cooperating annular ridge and groove intermediate the edges, inserting a gelatin capsule having fluid under pressure into the hollow section and tting said core sections together to enclose the capsule with the ridge and groove in interlocked relationship and bonding said sections together under heat and pressure to form a spherical core, said heat melting the gelatin and freeing the uid under pressure to press the core portion into engagement with the inner part of the ridge to seal the core thereat, winding and elastic strand under tension about the center to form said spherical core with the interlock between the sections maintaining the core spherical during the winding Operation and the tension in the winding pressing the outer walls of the groove into sealing relation with the ridge to prevent leakage of uid from the center to the windings, and molding a cover around said winding.

References Cited in the tile of this patent UNITED STATES PATENTS 1,240,438 Gn'fths Sept. 13, 1917 2,166,950 German et al July 25, 1939 2,363,086 Ryan Nov. 21, 1944 FOREIGN PATENTS 25,053 Australia July 25, 1906 UNITED .STATES PATENT. OFFICE CERTIFICATE 0E CORRECTION `Patent No 2398,97? i September 5, 1.961

Robert P., Molitor It is hereby certified that error appears in the above numbered petent requiring correction and that the said Letters Patent should read as corrected below.

Column 4, Iina 72, under tha heading FOREIGN PATENTS," for "Australia" read Austria signed and sealed this 16th day of January 1962..

(SEAL) Attest:

ERNEST W. SWIDER DAVID L. LADD Attesting Officer Commissioner of Patents 

